Blended gasoline



Patented June25, 1946 BLENDED GASOLINE Hilbertll. Zuiderna, Edwardsville, and John E.

Mital, Alton, Ill., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application Noveinber Serial No. 510,226

9 Claims This invention relates to blended gasoiines' of improved stability, and is more particularly concerned with leaded gasolines containing up to about and preferably between. about /2 and 7% alicyclic olefines preferably containing a cyclohexene ring.

Cracked gasolines have always been considered relatively unstable in contrast to straight run gasoline because the iormer'contain olefines while the latter do not. This difierence in stability has been known to be further aggravated by the presence of tetra ethyl lead, tetra ethyl lead blends of cracked gasolines being notoriously unstable unless strongly inhibited with an inhibitor serving to stabilize both the olefines as well as the tetra ethyl lead.

We'have now discovered that the presence of. cyclic olefines, preferably containing a C6 cyclo olefine ring, in amounts up to about 10% in various gasolines tends to stabilize the gasoline rather than render it unstable. as herein defined are alicyclic hydrocarbons containing an oleflnic double bond in the ring. Our. invention therefore comprises adding to a gasoline containing little or no cyclic olefines, whether inhibitors such as those based on paraphenylene diamine, para amino phenol and alpha naphthylamine, etc. Examples of such inhibitors are the N,N'dibutyl para phenylene diamine, benzyl para amino phenol, Other inhibitors such as the purely. phenolic inhibitors, as for example 2,4-dimethyl fi-tertiary butyl phenol or 4-methyl 2,6-ditertiary butyl phenol, etc., 'while enhancing the stabilityhof our blended gasolines are not quite as effective as those mentioned above.

The effect of various olefines, both cyclic and aliphatic, on the induction periods of an alkylate gasoline containing 4 cc. tetra ethyl lead per gallon, being itself substantially free of oleflnes,

' is demonstrated in the tables below:

Cyclic olefines oleflnes in.-amounts such that the concentration of cyclic oleflnes in the final blend is not above about 10% by volume and preferably between about and 7%. The blended gasoline may contain tetra ethyl lead in the usual amounts. e.g. up to about 5 or 6 -cc./gal., and preferably should contain effective amounts of an oxidation inhibitor. The added cyclo olefines should boil within gasoline boiling range, and may, if desired, contain (preferably not more than one) olefinic double bondother than the one in the ring.

Possible sources of alicyclic oleflnes include the terpenes. Other cyclic. olefines may be prepared by various syntheses, such as partial dehydrogenation of naphthenes. Individual cyclic olefines suitable for the purpose include cyclohexene, methyl cyclohexene, dimethyl cyclohexene, trimethyl cyclohexene, ethyl cyclohexene, methyl ethyl cyclohexene, etc.; terpenes, such as di-limonene (citrene), d+l-limonene, (dipentene), terpinolene, alpha, beta or gamma terpinene,.phel-, landrene; dihydroterpenes such as menthene,

carvomenthene, eta; cyclopentene, methyl cyclopentene, dimethylcyclopentene, ethyl cyclopentene, etc.

Usually the content of cyclo olefines in gasolines is quite low, below about /2'%. Therefore, the addition or cyclo olefines generally results in some improvement. v

Diflerent' types of oxidation inhibitors afiectv the stability of the blended gasoline somewhat difierently. Especially useful are aromatic amino Table I v Induction Beriod hours (100 p.s.i. 1811100 U.) I Per cent med Near u Uninhibited 5 many cue mine None i 0 Cyclohexene 41. 0 I 96+ 96+ 1 a? D en ene p 90. 0 I 9 10 21. 5 Mixed amylenes 8. 4 10 5. 6 Di-isobutylene M 5 6 23. 1 2 5. 9 21. 2 l0 6. 2 22. 4

1 d, l-Limonene.

demonstrated below:

The amount ofthe oxidation inhibitors em phenyl alpha naphthylamine.

' 3 played in our gasoline do not difler from those customarily employed. Thus these amounts are 1101111811? 1988 t n and usually between .001 and .0195.

Other additives such as aniline, methyl aniline,

iln content 01' the resulting blend is about Vz%.'

2. A naturally unstable gasoline stabilized against oxidation by the addition of a Ca cycloolefin boiling within gasoline boiling range and possessing a single double bond in the ring, in an amount such that the cycloolefln content of the resulting blend is about /2%.

3. A naturally unstable gasoline stabilized against oxidation by the addition of a cyclohexene boiling within gasoline boiling range, in an amount such that the cycloolefln content of the resulting blend is about 4.- A naturally unstable gasoline stabilize 4 against oxidation by the addition oia' terpene boiling within gasoline boiling range and possessing a single double bond in the ring, in an amountsuch that the cycloolefln content of the resulting blend is about /2 V 5. A cracked, unstable gasoline stabilized against oxidation by the addition of a cycloolefin boiling within gasoline boiling range and possessing a single'double bond in the ring, in an amount such that the cycloolefln content of the and possessing a single double bond in the ring,

in anamount such that the cycloolefin content of the resulting blend is about l '7. A composition comprising a naturally unstable gasoline stabilized against oxidation by the addition of an aromatic amino oxidation inhibitor and or between about /2% and 10% oi a cycloolefin boiling within the gasoline boiling range and possessing a single double bond in the ring.

8. A composition according to claim '7, wherein the cycloolefln content is below about 7%.

-9. A composition according to claim 7, wherein the cycloolefln content is in the neighborhood of about Vz%- v HIIBERT H. ZUIDEMA. JOHN E. MITAL. 

